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- 2017
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:2
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Rauer, H., et al.
(författare)
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The PLATO 2.0 mission
- 2014
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Ingår i: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 38:1-2, s. 249-330
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Tidskriftsartikel (refereegranskat)abstract
- PLATO 2.0 has recently been selected for ESA's M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it addresses fundamental questions such as: How do planetary systems form and evolve? Are there other systems with planets like ours, including potentially habitable planets? The PLATO 2.0 instrument consists of 34 small aperture telescopes (32 with 25 s readout cadence and 2 with 2.5 s cadence) providing a wide field-of-view (2232 deg(2)) and a large photometric magnitude range (4-16 mag). It focuses on bright (4-11 mag) stars in wide fields to detect and characterize planets down to Earth-size by photometric transits, whose masses can then be determined by ground-based radial-velocity follow-up measurements. Asteroseismology will be performed for these bright stars to obtain highly accurate stellar parameters, including masses and ages. The combination of bright targets and asteroseismology results in high accuracy for the bulk planet parameters: 2 %, 4-10 % and 10 % for planet radii, masses and ages, respectively. The planned baseline observing strategy includes two long pointings (2-3 years) to detect and bulk characterize planets reaching into the habitable zone (HZ) of solar-like stars and an additional step-and-stare phase to cover in total about 50 % of the sky. PLATO 2.0 will observe up to 1,000,000 stars and detect and characterize hundreds of small planets, and thousands of planets in the Neptune to gas giant regime out to the HZ. It will therefore provide the first large-scale catalogue of bulk characterized planets with accurate radii, masses, mean densities and ages. This catalogue will include terrestrial planets at intermediate orbital distances, where surface temperatures are moderate. Coverage of this parameter range with statistical numbers of bulk characterized planets is unique to PLATO 2.0. The PLATO 2.0 catalogue allows us to e. g.: - complete our knowledge of planet diversity for low-mass objects, - correlate the planet mean density-orbital distance distribution with predictions from planet formation theories,- constrain the influence of planet migration and scattering on the architecture of multiple systems, and - specify how planet and system parameters change with host star characteristics, such as type, metallicity and age. The catalogue will allow us to study planets and planetary systems at different evolutionary phases. It will further provide a census for small, low-mass planets. This will serve to identify objects which retained their primordial hydrogen atmosphere and in general the typical characteristics of planets in such a low-mass, low-density range. Planets detected by PLATO 2.0 will orbit bright stars and many of them will be targets for future atmosphere spectroscopy exploring their atmospheres. Furthermore, the mission has the potential to detect exomoons, planetary rings, binary and Trojan planets. The planetary science possible with PLATO 2.0 is complemented by its impact on stellar and galactic science via asteroseismology as well as light curves of all kinds of variable stars, together with observations of stellar clusters of different ages. This will allow us to improve stellar models and study stellar activity. A large number of well-known ages from red giant stars will probe the structure and evolution of our Galaxy. Asteroseismic ages of bright stars for different phases of stellar evolution allow calibrating stellar age-rotation relationships. Together with the results of ESA's Gaia mission, the results of PLATO 2.0 will provide a huge legacy to planetary, stellar and galactic science.
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| 3. |
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| 4. |
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| 5. |
- Cockell, C.S., et al.
(författare)
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Habitability : a review
- 2016
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Ingår i: Astrobiology. - : Mary Ann Liebert Inc. - 1531-1074 .- 1557-8070. ; 16:1, s. 89-117
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Tidskriftsartikel (refereegranskat)abstract
- Habitability is a widely used word in the geoscience, planetary science, and astrobiology literature, but what does it mean? In this review on habitability, we define it as the ability of an environment to support the activity of at least one known organism. We adopt a binary definition of “habitability” and a “habitable environment.” An environment either can or cannot sustain a given organism. However, environments such as entire planets might be capable of supporting more or less species diversity or biomass compared with that of Earth. A clarity in understanding habitability can be obtained by defining instantaneous habitability as the conditions at any given time in a given environment required to sustain the activity of at least one known organism, and continuous planetary habitability as the capacity of a planetary body to sustain habitable conditions on some areas of its surface or within its interior over geological timescales. We also distinguish between surface liquid water worlds (such as Earth) that can sustain liquid water on their surfaces and interior liquid water worlds, such as icy moons and terrestrial-type rocky planets with liquid water only in their interiors. This distinction is important since, while the former can potentially sustain habitable conditions for oxygenic photosynthesis that leads to the rise of atmospheric oxygen and potentially complex multicellularity and intelligence over geological timescales, the latter are unlikely to. Habitable environments do not need to contain life. Although the decoupling of habitability and the presence of life may be rare on Earth, it may be important for understanding the habitability of other planetary bodies
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| 6. |
- Sumaila, U. Rashid, et al.
(författare)
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WTO must ban harmful fisheries subsidies
- 2021
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 374:6567, s. 544-544
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Douketis, J D, et al.
(författare)
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Perioperative bridging anticoagulation during dabigatran or warfarin interruption among patients who had an elective surgery or procedure : Substudy of the RE-LY trial
- 2015
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Ingår i: Thrombosis and Haemostasis. - : Georg Thieme Verlag KG. - 0340-6245 .- 2567-689X. ; 113:3, s. 625-632
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Tidskriftsartikel (refereegranskat)abstract
- In patients with atrial fibrillation (AF) who require interruption of dabigatran or warfarin for an elective surgery/procedure, the risks and benefits of perioperative bridging anticoagulation is uncertain. We accessed the database from RE-LY, a randomised trial comparing dabigatran with warfarin for stroke prevention in AF, to assess the potential benefits and risks of bridging. In patients who had a first interruption of dabigatran or warfarin for an elective surgery/procedure, we compared the risk for major bleeding (MB), stroke or systemic embolism (SSE) and any thromboembolism (TE) in patients who were bridged or not bridged during the period of seven days before until 30 days after surgery/procedure. We used multivariable Cox regression to adjust for potential confounders. Bridging was used more during warfarin interruption than dabigatran interruption (27.5 % vs 15.4 %; p< 0.001). With dabigatran interruption, bridged patients had more MB (6.5 % vs. 1.8 %, P< 0.001) than those not bridged but bridged and not bridged groups did not differ for any TE (1.2 % vs 0.6 %, p=0.16) and SSE (0.5 % vs 0.3 %, p=0.46). With warfarin interruption, bridged patients had more MB (6.8 % vs 1.6 %, p< 0.001) and any TE (1.8 % vs 0.3 %, p=0.007) than those not bridged but bridged and not bridged groups did not differ for SSE (0.5 % vs 0.2 %, p=0.321). In conclusion, in patients who interrupted dabigatran or warfarin for a surgery/procedure in the RE-LY trial, use of bridging anticoagulation appeared to increase the risk for major bleeding irrespective of dabigatran or warfarin interruption.
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| 10. |
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| 11. |
- Ezekowitz, Michael D., et al.
(författare)
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Long-term evaluation of dabigatran 150 vs. 110 mg twice a day in patients with non-valvular atrial fibrillation
- 2016
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Ingår i: Europace. - : Oxford University Press (OUP). - 1099-5129 .- 1532-2092. ; 18:7, s. 973-978
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Tidskriftsartikel (refereegranskat)abstract
- Aims The Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) trial allowed patients who completed the trial receiving their assigned dabigatran 150 mg (D150) or 110 mg (D110) twice a day to continue into the Long-term Multicenter Extension of Dabigatran Treatment in Patients with Atrial Fibrillation (RELY-ABLE) trial. This permitted assessment of outcomes over a median of 4.6 and a maximum of 6.7 years, respectively. Methods and results The analysed population included only those patients who completed RE-LY on dabigatran and continued into RELYABLE without interruption of assigned dabigatran. Cumulative risk was expressed as Kaplan-Meier plots. Outcomes were compared using Cox proportional hazard modelling. Stroke or systemic embolization rates were 1.25 and 1.54% per year (D150 and D110, respectively); hazard ratio (HR) 0.81 [95% confidence interval (CI): 0.68-0.96] (P = 0.02). Ischaemic stroke was 1.03 (D150) and 1.29%/year (D110); HR 0.79 (95% CI: 0.66-0.95) (P = 0.01). Haemorrhagic stroke rates were 0.11 (D150) and 0.13%/year (D110); HR 0.91 (95% CI: 0.51-1.62) (P = 0.75). Rates of major haemorrhage were 3.34 (D150) and 2.76%/year (D110); HR 1.22 (95% CI: 1.08-1.37) (P = 0.0008). Intracranial haemorrhage rates were 0.32 (D150) and 0.23%/year (D110); HR 1.37 (95% CI: 0.93-2.01) (P = 0.11). Mortality was 3.43 (D150) and 3.55%/year (D110); HR 0.97 (95% CI: 0.87-1.08) (P = 0.54). Conclusion Annualized rates of all outcomes were constant with better efficacy of D150, less major bleeding with D110, and low intracerebral haemorrhage rates for both doses. There were no additional safety concerns. This is the longest continuous randomized experience of a novel anticoagulant.
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| 12. |
- Hedlund, Jonas, et al.
(författare)
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ZSM-5 membranes synthesized without organic templates using a seeding technique
- 1999
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Ingår i: Journal of Membrane Science. - 0376-7388 .- 1873-3123. ; 159:1-2, s. 263-273
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Tidskriftsartikel (refereegranskat)abstract
- Porous α-alumina supports were seeded with colloidal TPA-silicalite-1 crystals and calcined. The supports were treated in a synthesis solution to grow the seed crystals into ZSM-5 films. The synthesis solution was free from organic template molecules in order to avoid the calcination step which often introduces cracks in the synthesized zeolite film. An SEM investigation indicated that the zeolite films on the supports were defect free and that the film thickness was approximately 1.5 μm. XRD data showed that the film consisted of well-crystallized ZSM-5. The permeance in single gas experiments decreased in the order H2O, H2, CO2, O2, N2 and CH4. The difference in permeance between each molecular species in the series was almost one order of magnitude which indicated that the membranes were of a high quality. Molecules larger than CH4 permeated with similar and low rates, independent of their kinetic diameters, indicating a non-selective permeation path through defects in the zeolite films. However, the permeance of these larger molecules was less than 1/10 000 of that for H2O. The highest measured separation factors for binary mixtures of N2/SF6 and H2/i-C4 were 110 and 99.
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| 13. |
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| 14. |
- Moiseenko, Vladimir E., et al.
(författare)
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Fusion with fission power amplification
- 2008
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Ingår i: Problems of atomic science and technology. - 1562-6016. ; :6, s. 55-57
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Tidskriftsartikel (refereegranskat)abstract
- A scheme of a sub-critical system driven by fusion neutrons from a stellarator-mirror device is considered. In addition, a power production scheme which uses fusion power amplification by depleted uranium mantle is discussed.
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| 16. |
- Noack, P., et al.
(författare)
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Family relations in adolescence
- 1999
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Ingår i: Journal of Adolescence. - : Elsevier BV. - 0140-1971 .- 1095-9254. ; 22:6, s. 713-717
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Tidskriftsartikel (refereegranskat)
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| 17. |
- Quanz, S. P., et al.
(författare)
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Large Interferometer For Exoplanets (LIFE) I. Improved exoplanet detection yield estimates for a large mid-infrared space-interferometer mission
- 2022
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 664
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Tidskriftsartikel (refereegranskat)abstract
- Context. One of the long-term goals of exoplanet science is the atmospheric characterization of dozens of small exoplanets in order to understand their diversity and search for habitable worlds and potential biosignatures. Achieving this goal requires a space mission of sufficient scale that can spatially separate the signals from exoplanets and their host stars and thus directly scrutinize the exoplanets and their atmospheres.Aims. We seek to quantify the exoplanet detection performance of a space-based mid-infrared (MIR) nulling interferometer that measures the thermal emission of exoplanets. We study the impact of various parameters and compare the performance with that of large single-aperture mission concepts that detect exoplanets in reflected light.Methods. We have developed an instrument simulator that considers all major astrophysical noise sources and coupled it with Monte Carlo simulations of a synthetic exoplanet population around main-sequence stars within 20 pc of the Sun. This allows us to quantify the number (and types) of exoplanets that our mission concept could detect. Considering single visits only, we discuss two different scenarios for distributing 2.5 yr of an initial search phase among the stellar targets. Different apertures sizes and wavelength ranges are investigated.Results. An interferometer consisting of four 2 m apertures working in the 4–18.5 μ.m wavelength range with a total instrument throughput of 5% could detect up to ≈550 exoplanets with radii between 0.5 and 6 R⊕ with an integrated S/N ≥ 7. At least ≈160 of the detected exoplanets have radii ≤1.5 R⊕. Depending on the observing scenario, ≈25–45 rocky exoplanets (objects with radii between 0.5 and 1.5 R⊕) orbiting within the empirical habitable zone (eHZ) of their host stars are among the detections. With four 3.5 m apertures, the total number of detections can increase to up to ≈770, including ≈60–80 rocky eHZ planets. With four times 1 m apertures, the maximum detection yield is ≈315 exoplanets, including ≤20 rocky eHZ planets. The vast majority of small, temperate exoplanets are detected around M dwarfs. The impact of changing the wavelength range to 3–20 μm or 6–17 μm on the detection yield is negligible.Conclusions. A large space-based MIR nulling interferometer will be able to directly detect hundreds of small, nearby exoplanets, tens of which would be habitable world candidates. This shows that such a mission can compete with large single-aperture reflected light missions. Further increasing the number of habitable world candidates, in particular around solar-type stars, appears possible via the implementation of a multi-visit strategy during the search phase. The high median S/N of most of the detected planets will allow for first estimates of their radii and effective temperatures and will help prioritize the targets for a second mission phase to obtain high-S/N thermal emission spectra, leveraging the superior diagnostic power of the MIR regime compared to shorter wavelengths.
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